Parking brake device for vehicle

ABSTRACT

A device provided with a pedal arm ( 2 ) having pawl teeth ( 12 ), a latch pawl member ( 4 ) having a latch pawl ( 15 ) engageable with the pawl teeth ( 12 ) for maintaining and releasing a stepped-on position of the pedal arm ( 2 ), and a position changing member ( 5 ) for allowing the latch pawl member ( 4 ) to maintain the position of the pedal arm ( 2 ) when the pedal arm is further stepped on from a maintained position. The above constitution realizes a function of setting a braking force by a stepping operation, a function of releasing a braking force by a stepping operation and a function of increasing a braking force by an additional stepping operation.

This application is a 371 of PCT/JP00/04152 filed Jun. 23, 2000.

TECHNICAL FIELD

The present invention relates to a parking brake device for a vehiclehaving a releasing system of a foot-operated type.

BACKGROUND ART

Vehicle parking brake devices are largely classified into ahand-operated type and a foot-operated type depending upon the operatingform. Foot-operated parking brake devices are being spread mainly amonghigh-grade cars. Many types of foot-operated parking brake devices havebeen conventionally proposed, and as one of those, a full foot-operatedparking brake device in which not only a braking operation (namely, anoperation for setting a braking force) but also a releasing operationare conducted by a stepping operation is known.

In a foot-operated parking brake device, there may occur a situation inwhich, although a braking force is once set by a stepping operation, theamount of stepping is not sufficient and thus a required braking forcecannot be obtained. In such a case, an operation for increasing thebraking force is required.

However, conventional parking brake devices, in which, when a pedal isfurther stepped on from an initially set position (so-called “additionalstepping operation”), a function of maintaining the pedal position atthe moment is released, namely, a braking release operation isconducted, do not have a function of maintaining the pedal at a positionafter the additional stepping. Thus, when a larger braking force isdesired (namely, braking force is desired to be increased) after abraking operation has been conducted to set a braking force, thefunction of maintaining the pedal position at the moment must be oncereleased to restore the pedal to a set state before the brakingoperation (namely, the braking force must be vanished). Then, the pedalmust be stepped on beyond the initial stepped-on position to a requiredstepped-on position to set a braking force once again, and an operationfor maintaining the condition must be conducted.

As a result, in the conventional parking brake devices, the operation atthe time when an increase of the braking force is desired is complicatedand thus the operability thereof is poor. Additionally, in the brakingforce changing operation, the braking force already set is once vanishedand a braking force must be set again. Thus, there is no continuity ofthe braking force before and after the braking force changing operation,resulting in impairment in reliability during operation.

In view of the problems of such a conventional foot-operated parkingbrake device for a vehicle, the present invention is aimed at improvingthe operability thereof by allowing a braking force to be increased byan additional stepping operation and enhancing the reliability thereofduring operation by securing a continuity of the braking force duringthe braking force increasing operation.

DESCRIPTION OF THE INVENTION

According to one aspect of the present invention there is provided aparking brake device for a vehicle having brake means, comprising:

a pedal arm (2) having pawl teeth (12) and operatively connected to saidbrake means such that said brake means performs a braking action whensaid pedal arm is stepped on;

a latch pawl member (4) including a latch pawl (15) engageable with saidpawl teeth (12) of said pedal arm (2), movable between a locked positionin which said latch pawl (15) is in locking engagement with said pawlteeth (12) and an unlocked position in which said locking engagement ofsaid latch pawl (15) with said pawl teeth (12) is released, said latchpawl member (4) assuming said locked position, when said pedal arm (2)is stepped on, to maintain said pedal arm (2) in a stepped-on positionat the moment and assuming said unlocked position, when said pedal arm(2) is further stepped on from said stepped-on position by a determinedamount, to allow said pedal arm (2) to rotate in a direction opposite tothe stepping direction thereof;

a position changing member (5) supported on a common support shaft (9)for said latch pawl member (4) and provided with a latch pawl (22)engageable with said pawl teeth (12) of said pedal arm (2), saidposition changing member (5) being operatively connected to said pedalarm (2) and said latch pawl member (4) and adapted for shifting saidlatch pawl member (4) from said unlocked position to said lockedposition by a stepping force applied to said pedal arm (2) when saidpedal arm (2) is stepped on by an amount over said determined amount;

a first engaging portion (23) provided on said position changing member(5) and engageable with said latch pawl member (4) when said latch pawlmember (4) assumes said locked position to maintain said positionchanging member (5) at such a position that said latch pawl (22) isseparated from said pawl teeth (12) of said pedal arm (2); and

a second engaging portion (24) provided on said position changing member(5) and engageable with said latch pawl member (4) when said latch pawlmember (4) assumes said unlocked position to maintain said positionchanging member (5) at such a position that said latch pawl (22) isengaged by said pawl teeth (12) of said pedal arm (2).

In another aspect, the present invention provides a parking brake devicefor a vehicle having brake means, comprising:

a pedal arm (42) rotatably mounted on a mounting bracket (41) fixedlydisposed on a vehicle body and operatively connected to said brake meanssuch that said brake means performs a braking action when said pedal armis stepped on;

a pawl teeth member (43) including pawl teeth (52) and fixed to saidmounting bracket (41);

a latch pawl member (44) including a latch pawl (55) engageable withsaid pawl teeth (52) of said pawl teeth member (43), movable between alocked position in which said latch pawl (55) is in locking engagementwith said pawl teeth (52) and an unlocked position in which said lockingengagement of said latch pawl (55) with said pawl teeth (52) isreleased, said latch pawl member (44) assuming said locked position,when said pedal arm (42) is stepped on, to maintain said pedal arm (42)in a stepped-on position at the moment and assuming said unlockedposition, when said pedal arm (42) is further stepped on from saidstepped-on position by a determined amount, to allow said pedal arm (42)to rotate in a direction opposite to the stepping direction thereof;

a position changing member (45) supported on a common support shaft (49)for said latch pawl member (44) and operatively connected to said pedalarm (42) and said latch pawl member (44) for shifting said latch pawlmember (44) from said unlock position to said locked position by astepping force applied to said pedal arm (42) when said pedal arm (42)is stepped on by an amount over said determined amount;

and an engaging portion (64) provided on said position changing member(45) and engageable with said latch pawl member (44) when said latchpawl member (44) assumes said locked position to maintain the positionof said position changing member (45), and with said latch pawl member(44) when said latch pawl member (44) assumes said unlocked position tomaintain the position of said latch pawl member (44).

The preferred embodiments of the present invention will be hereinafterdescribed in detail with reference to the drawings, in which

FIG. 1 is a view explanatory of an essential part of a parking brakedevice for a vehicle according to a first embodiment of the presentinvention in a set state;

FIG. 2 is a perspective exploded view illustrating the on-assemblingstate of the major constructional members of the parking brake devicefor a vehicle shown in FIG. 1;

FIG. 3 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 during a stroke;

FIG. 4 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 in a lockedstate;

FIG. 5 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 in an unlockedstate;

FIG. 6 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 in a stateimmediately before setting;

FIG. 7 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 at the time whenan additional stepping is started;

FIG. 8 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 during anadditional stepping stroke;

FIG. 9 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 in a state inwhich the additional stepping has been completed;

FIG. 10 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 1 in a locked stateafter the completion of an additional stepping;

FIG. 11 is a view explanatory of the structure of an essential part of aparking brake device for a vehicle according to a second embodiment ofthe present invention in a set state;

FIG. 12 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 11 in a lockedstate;

FIG. 13 is a view explanatory of the structure of an essential part ofthe parking brake device for a vehicle shown in FIG. 11 in an unlockedstate;

FIG. 14 is a view explanatory of the structure of the parking brakedevice for a vehicle shown in FIG. 11 during a return movement of apedal;

FIG. 15 is a view explanatory of the structure of the parking brakedevice for a vehicle shown in FIG. 11 at the time of an additionalstepping;

FIG. 16 is a front view of a latch pawl member shown in FIG. 11; and

FIG. 17 is a front view of a position changing member shown in FIG. 11.

First Embodiment

FIG. 1 shows an essential part of a parking brake device for a vehicleaccording to a first embodiment of the present invention, and FIG. 2shows an on-assembling state of the constructional members thereof. Inthese Figures, designated as 1 is a mounting bracket secured to a bodyside member 11, as 2 is a pedal arm, which is step-operated by a driver.The pedal arm 2 has a foot plate 27 at one end 2 a thereof. To the otherend 2 b of the pedal arm 2 is secured a pawl teeth member 3 having pawlteeth 12 extending in an arc outwardly from the other end 2 b.

The pawl teeth member 3 has one end side provided with a retreat portion14 located at a level lower than the pawl teeth 12. A guide plate 13extending in a direction perpendicular to the plane direction of thepedal arm 2 is provided at a position a predetermined distance outwardlyaway from the retreat portion 14 in the plane direction of the pedal arm2.

The pedal arm 2 constituted as above is rotatably supported at aposition near the other end on a pedal support pin 8 protruded from themounting bracket 1, whereby the pedal arm 2 is mounted on the mountingbracket 1. With the pedal arm 2 mounted on the mounting bracket 1, oneend of a parking cable 10 is connected to the pedal arm 2 at a positionin the vicinity of the other end 2 b. The other end of the parking cable10 is connected to brake means 75. The parking cable 10 is normallypulled toward a pull-in side (in the direction of the arrow a) so thatthe pedal arm 2 is normally rotationally urged in a direction (thedirection of the arrow B) opposite to the stepping direction (thedirection of the arrow A) by a tensile force of the parking cable 10. Inthis embodiment, as shown in FIG. 1, a handbrake mechanism comprising adrum 76 and a band 77 is employed as the brake means 75, which isintegrally installed into brake means 71 for a main brake deviceincluding a brake disc 72 and a caliper 73. The other end of the parkingcable 10 is connected to an end portion 77 a of the band 77. As thebrake means 75, any commonly used means may be employed for the purposeof the present invention.

When a stepping force is applied onto the foot plate 27, the pedal arm 2is stepped on against a rotational urging force caused by the tensileforce of the parking cable 10 and rotated in the direction of the arrowA. Along with the rotation of the pedal arm 2, the parking cable 10 ispulled in the direction of the arrow b so that a braking forcecorresponding to the amount of stepping (the amount of rotation) of thepedal arm 2 is exerted on the brake means 75.

The mounting bracket 1 has a spindle 9 fixedly erected at a positionproperly remote from the pawl teeth member 3, and a latch pawl member 4and a position changing member 5, which will be hereinafter described,are mounted thereon.

As shown in FIG. 2, the latch pawl member 4 is a plate having agenerally ellipse shape and has a slot 20 formed at a generally centerpart thereof with its major axis generally coinciding with thelongitudinal direction thereof. On the periphery of the latch pawlmember 4A in one end in the longitudinal direction thereof, there areformed a pawl 15 having a shape engageable with the pawl teeth 12 of thepawl teeth member 3 and a sliding contact engagement portion 16 havingan arcuate surface at opposed positions in the direction of the minoraxis of the slot 20. A linear latch portion 21 is formed at a positionon the periphery of the latch pawl member 4 on the other end side in thelongitudinal direction thereof and on the same side as the slidingcontact engagement portion 16. A linearly extending first contactportion 17 is formed at a position on the same side as the pawl 15 andopposed to the latch portion 21, and a corner-shaped second contactportion 18 is formed at an end part of the first contact portion 17. Anotch like catch portion 19 is formed at a position on the same side asthe sliding contact engagement portion 16 and the latch portion 21 andgenerally corresponding to the slot 20.

The position changing member 5 is a plate having a slot 26 formed at aposition near one end in the longitudinal direction thereof and a catchportion 25 comprising a small hall formed at a position near the otherend thereof as shown in FIG. 2. A latch pawl 22 engageable with the pawlteeth 12 of the pawl teeth member 3 is formed at a position generallycorresponding to the slot 26 on the periphery of the position changingmember 5. A pair of engaging portions 23 and 24 extending in a directiongenerally perpendicular to the plane direction of the position changingmember 5 and opposed to each other are formed at positions between thecatch portion 25 and the slot 26 thereof.

As shown in FIG. 1 and FIG. 2, the support shaft 9 extends through theslot 20 of the latch pawl member 4 and the slot 26 of the positionchanging member 5 with the latch pawl member 4 laid upon on the sidefrom which the engaging portion 23 and 24 extend of the positionchanging member, whereby the latch pawl member 4 and the positionchanging member 5 are mounted on to the mounting bracket 1. In thisstate, the first and second engaging portions 23 and 24 of the positionchanging member 5 are opposed to the latch portion 21 of the latch pawlmember 4 and the first contact portion 17 of the position changingmember 5, respectively.

Relative movement of the support shaft 9 within the range of the slot 20and in the direction of the major axis thereof allows movement of thelatch pawl member 4 in the directions of the arrows C-D (the positionswhen the latch pawl member 4 is moved in the directions of the arrows Dand C may be hereinafter referred to as “forward position” and “reverseposition”, respectively, for the sake of convenience for explanation).Relative movement of the support shaft 9 within the range of the slot 26and in the direction of the major axis thereof allows movement of theposition changing member 5 in the directions of the arrows G-H (thepositions when the position changing member 5 is moved in the directionsof the arrows H and G are hereinafter referred to as “forward position”and “reverse position”, respectively, for the sake of convenience forexplanation).

With the latch pawl member 4 and the position changing member 5assembled on the mounting bracket 1, first and second urging members 6and 7 are assembled on the latch pawl member 4 and the position changingmember 5, respectively.

The first urging member 6 comprises a coil shaped torsion spring havingfirst stop portions 6 a and 6 a located at the opposed end thereof andeach fixedly inserted in catch holes 31 formed in the mounting bracket1, and a second stop portion 6 b located at the center part thereof andcaught in the catch portion 19 of the latch pawl member 4. The latchpawl member 4 is rotationally urged by an urging force of the firsturging member 6. In this case, the direction of rotation urged by thefirst urging member 6 varies depending upon the position of the latchpawl member 4. Namely, when the latch pawl member 4 is in the “forwardposition”, the second stop portion 6 b of the first urging member 6 islocated on the side of the latch pawl 15 with respect to a referenceline L₀, which is a straight line connecting the first stop portion 6 aof the first urging member 6 and the support shaft 9 as shown in FIG. 1so that the first urging member 6 is urged in such a direction that thelatch pawl 15 is moved closer to the pawl teeth member 3 (the directionof the arrow F) by an urging force of the first urging member 6. On theother hand, when the latch pawl member 4 is in the “reverse position”,the second stop portion 6 b of the first urging member 6 is located onthe other side of the latch pawl 15 with respect to the reference lineL₀ as shown in FIG. 5 so that the latch pawl member 4 is urged in such adirection that the latch pawl 15 is moved away from the pawl teethmember 3 (the direction of the arrow E) by the urging force of the firsturging member 6.

The second urging member 7 comprises a coil shaped torsion spring havinga first stop portion 7 a located at one end thereof and fixedly insertedin a catch hole 32 formed in a mounting bracket 1 and a second stopportion 7 b located at the other end thereof and caught in a catchportion 25 of the position changing member 5. The position changingmember 5 is normally urged to the side of the “reverse position” (in thedirection of the arrow G) by the second urging member 7. The positionchanging member 5 is, as described below, shifted from the “reverseposition” to the “forward position” along with the rotation of the pedalarm 2 in the stepping direction thereof (the direction of the arrow A)when the latch pawl 22 is locked with one of the pawl teeth 12 of thepawl teeth member 3. The position changing member 5 is, as describedbelow, rotated following the rotation of the latch pawl member 4 in thedirections of the arrows E-F in such a directions that the latch pawl 22is moved away from and closer to the pawl teeth 12 of the pawl teethmember 3 (the directions of the arrows I-J).

The operation of the parking brake device for a vehicle of thisembodiment will be next described with reference to FIG. 1 to FIG. 10.

{circle around (1)} Set state (see FIG. 1)

A set state shown in FIG. 1 is a condition in which no steppingoperation is conducted on the pedal arm 2 as when the vehicle is runningand thus the parking cable 10 has been pulled back in the direction ofthe arrow “A so that no braking force is exerted on the brake means 75.In this set state, the latch pawl member 4 is in the “forward position”.Thus, the latch pawl member 4 is urged in the direction of the arrow Fby the urging force of the second stop portion 6 b and the latch pawl 15abuts on the retreat portion 14 of the pawl teeth member 3 (in thisstate, the sliding contact engagement portion 16 of the latch pawlmember 4 is in engagement with the guide plate 13 of the pedal arm 2,whereby the position of the latch pawl member 4 is maintained). Theposition changing member 5 is set at the “reverse position” by thesecond urging member 7. The catch portion 21 of the latch pawl member 4is in engagement with the first engaging portion 23 of the positionchanging member 5, whereby the position changing member 5 has beenrotated in the direction of the arrow I corresponding to the position ofthe latch pawl member 4.

{circle around (2)} At the time of braking operation from the set state(see FIG. 1, FIG. 3 and FIG. 4)

When the pedal arm 2 in the set state shown in FIG. 1 is stepped on androtated in the direction of the arrow A, the latch pawl 15 of the latchpawl member 4 is slid on the retreat portion 14 of the pawl teeth member3 to the side of the pawl teeth 12 by the rotation of the pawl teethmember 3 along with the rotation of the pedal arm 2, and moved incontact with the pawl teeth 12 while the stepping operation of the pedalarm 2 is continued (the state shown in FIG. 3).

When the stepping operation of the pedal arm 2 is ceased and thestepping force is released, the pedal arm 2 inversely rotated in thedirection of the arrow B by a tensile force of the parking cable 10 asshown in FIG. 4. At this time, the latch pawl 15 of the latch pawlmember 4 is locked with one of the pawl teeth 12 abutting thereon atthat time. Thus, the latch pawl member 4, which receives a rotationalforce of the pedal arm 2 in the direction of the arrow B with itslocking position maintained, is shifted from the “forward position” tothe side of the “reverse position” and stopped at the “reverse position”(a state shown in FIG. 4, and the position of the latch pawl member 4 atthis time is the locked position mentioned in Claims). In this state,the stepped-on position of the pedal arm 2 is maintained by the latchpawl member 4 and thus the brake means 75 maintains the braking force atthe moment (namely, the braking operation is completed).

In this state, since the latch pawl member 4 is set at the “reverseposition” as shown in FIG. 4, the second stop portion 6 b of the firsturging member 6 is located on the other side of the latch pawl 15 withrespect to the reference line L₀, and the latch pawl member 4 isrotationally urged in such a direction that the latch pawl 15 is movedaway from the pawl teeth member 3 (the direction of the arrow E) by theurging force of the first urging member 6. However, an action forregulating the position of the latch pawl member 4 by a locking forceacting between the latch pawl 15 and the pawl teeth 12 surpasses theabove rotational urging force so that the latch pawl member 4 maintainsthe rotational position thereof.

{circle around (3)} Braking release operation (see FIG. 5 and FIG. 6)

At the time of a braking release operation by which the braking force isreleased from the state shown in FIG. 4 in which the braking force ismaintained to permit the vehicle to run, the pedal arm 2 is firstslightly stepped on and rotated in the direction of the arrow A as shownin FIG. 5 (the “amount of rotation” is sufficient when it is largeenough to be able to release the locking engagement of the pawl teeth 12with the latch pawl 15, and corresponds to “determined amount” mentionedin claims). Then, the latch pawl member 4 is released from the lockingengagement with one of the pawl teeth 12 of the pawl teeth member 3 androtated in the direction of the arrow E by the urging force of the firsturging member 6. At this time, since the first contact portion 17 of thelatch pawl member 4 is brought into engagement with the second engagingportion 24 of the position changing member 5 by the rotation of thelatch pawl member 4, the position changing member 5 is rotated in such adirection that the latch pawl 22 is moved closer to the pawl teeth 12(the direction of the arrow J) and the latch pawl 22 is locked at adetermined position on the pawl teeth 12 (the state shown in FIG. 5).

In this state, however, the position changing member 5 (and the latchpawl member 4) is rotatable against the urging force of the first urgingmember 6 in such a direction that the latch pawl 15 is moved away fromthe pawl teeth 12. Thus, in this state, when the stepping force appliedto the pedal arm 2 is released and the pedal arm 2 is rotated in thedirection of the arrow B by the tensile force of the parking cable 10 asshown in FIG. 6, the latch pawl 22 of the position changing member 5 isslid on the pawl teeth 12, thereby allowing a rotation of the pedal arm2 (the position of the latch pawl member 4 at the moment is the unlockedposition mentioned in claims).

Then, as shown in FIG. 6, when the latch pawl 15 of the latch pawlmember 4 comes to a position in the vicinity of an end of the pawl teeth12, the sliding contact engagement portion 16 of the latch pawl member 4is brought into engagement with the guide plate 13 of the pedal arm 2.Thus, when the pawl arm 2 is further restored, the latch pawl member 4is pressed by the guide plate 13 and the latch pawl 15 thereof ispositioned on the side of the retreat portion 14 of the pawl teethmember 3. In this case, the latch pawl member 4 is gradually forced torotate in the direction of the arrow F along with the rotation of thepedal arm 2 in the direction of the arrow B. Since the second stopportion 6 b of the first urging member 6 is moved to the side of thelatch pawl 15 with respect to the reference line L₀ along with therotation of the latch pawl member 4, the latch pawl member 4 is shiftedfrom the “reverse position” to the side of the “forward position” by theurging force of the first urging member 6, and eventually brought intothe set state shown in FIG. 1. Thereby, the action required for thebraking release operation is completed.

{circle around (4)} Operation for increasing braking force from abraking state by additional stepping (see FIG. 7 to FIG. 10)

In a braking state shown in FIG. 4, a braking force corresponding to theamount of stepping of the pedal arm 2 is obtained. When the brakingforce already set is smaller than that desired by the driver and anadditional increase in the braking force is required, a braking forceincreasing operation is conducted. Namely, in a state shown in FIG. 4,the pedal arm 2 is slightly stepped on into the released state shown inFIG. 5. After that, the pedal arm 2 is stepped on by a desired amount toincrease the braking force applied to the brake means 75. Morespecifically, when the pedal arm 2 is further stepped on from thebraking released state shown in FIG. 5, the latch pawl 22 of theposition changing member 5 has already locked with one of the pawl teeth12 of the pawl teeth member 3 by the above release operation so that theposition changing member 5 is allowed to rotate in such a direction thatthe latch pawl 22 is moved away from the pawl teeth 12 but inhibitedfrom rotating in such a direction that the latch pawl 22 is moved closerto the pawl teeth 12.

Thus, when the pedal arm 2 is stepped on, the position changing member 5is shifted from the “reverse position” to the side of the “forwardposition” along with the rotation of the pedal arm 2 in the direction ofthe arrow A as shown in FIG. 7. In this case, the second engagingportion 24 of the position changing member 5 is brought into engagementwith the second contact portion 18 of the latch pawl member 4, wherebythe latch pawl member 4 is shifted from the “reverse position” to theside of the “forward position” together with the position changingmember 5.

When the latch pawl member 4 reaches the “forward position”, the secondstop portion 6 b of the first urging member 6 has been moved to the sideof the latch pawl 15 with respect to the reference line L₀ as shown inFIG. 8, whereby the latch pawl member 4 is rotated in such a directionthat the latch pawl 15 is moved closer to the pawl teeth 12 by theurging force of the first urging member 6. Thereby, the latch pawl 15becomes lockable with the pawl teeth 12. Namely, the latch pawl member 4is in a state to allow the pedal arm 2 to rotate in the steppingdirection thereof with the latch pawl 15 thereof in sliding contact withthe pawl teeth 12. Thus, the pedal arm 2 can be continuously stepped onto a required stepped-on position (see FIG. 9).

The latch portion 21 of the latch pawl member 4 is brought intoengagement with the first engaging portion 23 of the position changingmember 5 along with the rotation of the latch pawl member 4, whereby theposition changing member 5 is rotated in such a direction that the latchpawl 22 is moved away from the pawl teeth 12 and shifted from the“forward position” to the “reverse position” by the urging force of thesecond urging member 7.

When the stepping force applied to the pedal arm 2 is released in thestate shown in FIG. 9 (namely, a state in which the additional steppingof the pedal arm 2 has been completed), the pedal arm 2 is inverselyrotated in the direction of the arrow B by the tensile force of theparking cable 10 as shown in FIG. 10 and the latch pawl 15 of the latchpawl member 4 is locked with one of the pawl teeth 12. Thus, the latchpawl member 4 is shifted from the “forward position” to the side of the“reverse position” by a rotational force of the pedal arm 2 andmaintains the stepped-on position of the pedal arm 2, namely the brakingforce of the brake means (the braking force after the increase).Thereby, the operation for increasing the braking force by additionalstepping is completed.

The operation and the action for releasing braking from the brakingstate after the completion of an increase of the braking force, whichare the same as those described in {circle around (3)}, are omittedhere.

Second Embodiment

FIG. 11 shows a parking brake device for a vehicle according to a secondembodiment of the present invention. The parking brake device, which isa foot-released type parking brake device having generally the sameconstitution as the parking brake device according to the firstembodiment on the whole, includes a mounting bracket 41, a pedal arm 42,a pawl teeth member 43, a latch pawl member 44, and a position changingmember 45, which will be hereinafter described. The major differencebetween the parking brake device of this embodiment and the parkingbrake device of the first embodiment is that in the parking brake deviceof the first embodiment the pawl teeth member 43 is disposed on the sideof the pedal arm 42 and the latch pawl member 44 and the positionchanging member 45 are disposed on the side of the mounting bracket 41whereas in the parking brake device of the second embodiment, on thecontrary, the pawl teeth member 43 is disposed on the side of themounting bracket 41 and the latch pawl member 44 and the positionchanging member 45 are disposed on the side of the pedal arm 42. Theparking brake device according to the second embodiment will behereinafter described in detail, considering the above difference.

The mounting bracket 41 is a plate having a determined thickness andfixedly disposed on a vehicle side member 51. A hereinafter describedpedal arm 42 is fixed to a generally center part of the mounting bracket41 via a pedal support pin 48 and a hereinafter described pawl teethmember 43 is secured to an edge on one end side thereof properly apartfrom the pedal support pin 48.

The pawl teeth member 43 is integrally formed by an arcuate plate andprovided with pawl teeth 52, 52 . . . on a peripheral surface thereof. Asliding contact engagement portion 54 comprising a lower level surfacecontinuing from the pawl teeth 52, 52 . . . is formed at one end side ofthe pawl teeth 52, 52 . . . The pawl teeth member 43 is secured to anedge of the mounting bracket 41 with the pawl teeth 52, 52 . . .directed outward in the plane direction of the mounting bracket 41. Theradius of curvature of the pawl teeth 52, 52 . . . and the fixingposition of the pawl teeth member 43 to the mounting bracket 41 aredetermined such that the pawl teeth 52, 52 . . . are located on an arcabout the pedal support pin 48.

The pedal arm 42, which is integrally formed by a plate, includes a baseend portion 42 a having a generally ellipse shape and a lever like endportion 42 b continuing from the base end portion 42 a and extendingfrontward. A foot plate 67 is mounted on the end portion 42 b. Along aperiphery of the base end portion 42 a is fixed a cable guide 68, aboutwhich an end side of a parking cable 50 is trained with the end securedthereto. The pedal arm 42 is pivoted on the side of the base end portion42 a by the pedal support pin 48 to the mounting bracket 41 rotatablyforward and backward about the pedal support pin 48. When the foot plate67 is stepped on, the pedal arm 42 is rotated about the pedal supportpin 48 in the direction of the arrow a and pulls the parking cable 50 toapply a braking force corresponding to the amount of stepping thereof tobrake means (not shown) connected to the other end of the parking cable50. When the stepping force applied to the foot plate 67 is released,the pedal arm 42 receives a tensile force from the brake means sidetransmitted via the parking cable 50 and is pulled down in the directionof the arrow b to be restored to a set position. Thereby, the brakingforce applied to the braking means is released.

A support shaft 49 is protruded from a position between the base endportion 42 a and the end portion 42 b of the pedal arm 42 and properlyremote from the periphery of the pawl teeth member 43 of the mountingbracket 41. A latch pawl member 44 and a position changing member 45,which will be hereinafter described, are mounted on the support shaft 49in overlapping relation in the thickness direction thereof.

As shown in FIG. 16, the latch pawl member 44 is an oblong plate havinga slot 60 formed in a generally center part thereof with its major axisextending in the longitudinal direction thereof. A contact portion 57having a linear catch surface and a guide portion 58 continuing from anend of the contact portion 57 and obliquely extending upward arerespectively formed at a position on one end side in the longitudinaldirection of the latch pawl member 44. A sliding contact engagementportion 56 having an arcuate shape is formed on the other end side inthe longitudinal direction of the latch pawl member 44. A latch pawl 55selectively engageable with one of the pawl teeth 52, 52 . . . of thepawl teeth member 43 is formed at one end side in the transversedirection of the latch pawl member 44 and a notch like catch portion 59is formed at the other end side in the transverse direction thereof.

The latch pawl member 44 is swingably supported on the pedal arm 42 bythe support shaft 49 secured to the pedal arm 42 and extending throughthe slot 60, whereby the latch pawl member 44 is rotatable about thesupport shaft 49 in the directions of the arrows e-f and slidabe in thedirection of the major axis of the slot 60 (the directions of the arrowsc-d). The positions when the latch pawl member 44 is slid in thedirections of the arrows c and d with respect to the support shaft 49are hereinafter referred to as “reverse position” and “forwardposition”, respectively, for convenience' sake of explanation as shownin FIG. 16.

In the catch portion 59 of the latch pawl member 44 is caught an actionend 46 a of a first urging member 46 comprising a torsion spring. A pairof support ends 46 a and 46 a of the first urging member 46 are hookedon the pedal arm 42. Thus, the position of the action end 46 b relativeto the support ends 46 a and 46 a is changed along with the rotation ofthe latch pawl member 44. In this embodiment, since the action end 46 bof the first urging member 46 is selectively movable to both sides of areference line L₀, which is a straight line connecting the fixingposition of the support ends 46 a and 46 a to the pedal arm 42 and theaxis of the support shaft 49, as shown in FIG. 11, a rotational urgingforce in the direction of the arrow e and a rotational urging force inthe direction of the arrow f are selectively applied to the latch pawlmember 44 based on the change of the position of the support ends 46 aand 46 a relative to the action end 46 b as described later.

The position changing member 45 is an oblong plate having an arcuateslot 66 extending in the longitudinal direction thereof formed at oneend side of the longitudinal direction thereof as shown in FIG. 17. Onthe other end side in the longitudinal direction of the latch pawlmember 44, there are provided an engaging portion 64 with which thecontact portion 57 of the latch pawl member 44 is engaged and first andsecond latch pawls 62 and 63 located on both side of the engagingportion 64. The first and second latch pawls 62 and 63, which areselectively engaged with the pawl teeth 52 of the pawl teeth member 43as described later, have no function for maintaining a position relativeto the pawl teeth member 43 (namely, locking function) even in thisengaged state.

The position changing member 45 is disposed in the vicinity of the latchpawl member 44 and in opposed relation therewith. As is the case withthe latch pawl member 44, the position changing member 45 is swingablysupported on the pedal arm 42 by the support shaft 49 secured to thepedal arm 42 and extending through the slot 66, whereby the positionchanging member 45 is rotatable about the support shaft 49 in thedirections of the arrows e-f and slidable along the arc of the slot 66 b(the directions of the arrows g-h, for convenience' sake). The positionswhen the position changing member 45 is slid in the directions of thearrows g and h with respect to the support shaft 49 are hereinafterreferred to as “reverse position” and “forward position”, respectively,for convenience' sake of explanation.

In the vicinity of the second latch pawl 54 of the position changingmember 45 is formed a catch portion 65, to which one end of a secondurging member 47 comprising a coil spring is connected. The other end ofthe second urging member 47 is connected to the pedal arm 42. Thus, theposition changing member 45 is normally rotationally urged in thedirection of the arrow e by a spring force of the second urging member47.

The spring force of the first urging member 46 is set at a value whichis larger than that of the second urging member 47.

The operation of the parking brake device according to this embodimentwill be hereinafter described with reference to FIG. 11 to FIG. 15.

{circle around (1)} Set state (see FIG. 11)

The set state shown in FIG. 11 is a state in which no braking force isapplied to the brake means as when the vehicle is running. The pedal arm42 has been rotated at maximum in the direction of the arrow b. In thisset state, since the action end 46 b of the first urging member 46 ispositioned above the reference line L₀ as shown in FIG. 11, the latchpawl member 44 has been forced upward by an urging force exerted on theaction end 46 b of the first urging member 46 into the “forwardposition” and is normally rotationally urged in the direction of thearrow e. The position changing member 45 has been forced downward by anurging force of the second urging member 47 into the “reverse position”.The engaging portion 64 abuts on the contact portion 57 of the latchpawl member 44. Thus, the contact portion 57 of the latch pawl member 44abuts on the retreat portion 54 of the pawl teeth member 43 and does notinhibit the pedal arm 42 from rotating at all. At this time, the slidingcontact engagement portion 56 of the latch pawl member 44 is positionedin the vicinity of a guide portion 53 of the mounting bracket 41 and inopposed relation therewith.

{circle around (2)} At the time of braking operation from the set state(see FIG. 11 and FIG. 12)

When the pedal arm 42 is stepped on from the set state shown in FIG. 11and rotated in the direction of the arrow a, the latch pawl 55 of thelatch pawl member 44 is moved from the side of the retreat portion 54 tothe side of the latch pawl member 44 by a forward movement of the latchpawl member 44 along with the rotation of the pedal arm 42, and moved onthe pawl teeth 52, 52, . . . , repeating engagement therewith anddisengagement therefrom while the rotating operation of the pedal arm 42is being continued. At this time, the latch pawl member 44 is urged bythe urging force of the first urging member 46 such that the latch pawl55 is constantly pressed against the pawl teeth 52, 52, . . . .

When the stepping operation of the pedal arm 2 is ceased and thestepping force applied thereto is released, a tensile force of theparking cable 50 is exerted on the pedal arm 42, which receives arestoring rotational force in the direction of the arrow b. At thistime, the support shaft 49 secured to the pedal arm 49 is moved upwardtogether therewith, and the latch pawl member 44 is shifted from“forward position” to the “reverse position” shown in FIG. 12. The latchpawl 55 of the latch pawl member 44 is locked with a specific tooth 52of the pawl teeth member 43 by a pressing force caused by the tensileforce of the parking cable 50 applied via the support shaft 49 andmaintained in that position. Namely, the braking force corresponding tothe amount of stepping of the pedal arm 42 is maintained (namely, in amaintained state after the completion of the braking operation).

In this case, the action end 46 b of the first urging member 44 is movedfrom above to below the reference line L₀ (see FIG. 12) along with themovement of the latch pawl member 44 from the “forward position” to the“reverse position”, and an urging force generated at the action end 46 bof the first urging member 46 urges the latch pawl member 44 in thedirection of the arrow f (namely, in such a direction that the latchpawl 55 is moved away from the pawl teeth 52 of the pawl teeth member43). However, the urging force of the first urging member 46 is smallerthan that caused by the tensile force of the parking cable 50 so thatthe position of the latch pawl member 44 is maintained with the latchpawl 55 in locking engagement with the pawl teeth 52 of the pawl teethmember 43 irrespective of the urging force of the first urging member46. The position of the latch pawl member 44 at this time is the lockedposition mentioned in claims.

{circle around (3)} Releasing operation of braking maintained state (seeFIG. 13)

When the braking maintained condition shown in FIG. 12 is released priorto releasing the braking force to allow the vehicle to run or conductingadditional stepping to increase the braking force, firstly, the pedalarm 42 is slightly stepped on from the rotational position in thebraking maintained condition and rotated in the direction of the arrow aas shown in FIG. 13 (the “amount of rotation” at this time is sufficientwhen it is large enough to be able to release the locking engagement ofthe latch pawl 55 with the pawl tooth 52, and corresponds to “determinedamount” mentioned in claims).

Then, since the pressing force exerted between the latch pawl 55 of thelatch pawl member 44 and the pawl teeth 52 of the pawl teeth member 43is vanished, the latch pawl member 44 is rotated in the direction of thearrow f by the urging force of the first urging member 46 and thelocking engagement of the latch pawl 55 with one of the pawl teeth 52 ofthe pawl teeth member 43 is released. The position of the latch pawlmember 44 at this time is the unlocked position mentioned in Claims.

At this time, along with the rotation of the latch pawl member 44 in thedirection of the arrow f, the rotational force thereof is transmittedvia the contact portion 57 of the latch pawl member 44 to the engagingportion 64 of the position changing member 45 so that the positionchanging member 45 is rotated in the direction of the arrow f againstthe urging force of the second urging member 8 and the second latch pawl63 thereof is brought into engagement with one of the pawl teeth 52 ofthe pawl teeth member 43, whereby the position changing member 45 isinhibited from further rotating in the direction of the arrow f.

The second latch pawl 63 of the position changing member 45 is pressedagainst the pawl teeth 52 of the pawl teeth member 43 by the differencebetween the urging force of the first urging member 46 and the urgingforce of the second urging member 8 so that the position changing member45 and the latch pawl member 44 are both rotatable in the direction ofthe arrow e.

{circle around (4)} Operation for releasing a braking force (see FIG. 13and FIG. 14)

When the braking force is vanished from the braking released state byrotating the pedal arm 42 in the direction of the arrow b, it is onlynecessary that the pedal arm 42 is rotated in the direction of the arrowb by the tensile force of the brake wire 10 from the state shown in FIG.13 (the state in which the braking maintained condition is released).

In this case, the second latch pawl 63 of the position changing member45 is slid on the pawl teeth 52, 52 . . . of the pawl teeth member 43,repeating engagement therewith and disengagement therefrom along withthe rotating operation of the pedal arm 42 in the direction of the arrowb and allows the pedal arm 42 to rotate in the direction of the arrow b.The latch pawl member 44 is moved backward along with the rotation ofthe pedal arm 42 in the direction of the arrow b so that the latch pawl55 thereof is moved away from the position corresponding to the pawlteeth 52, 52, . . . of the pawl teeth member 43 to the side of theretreat portion 54. Then, the sliding contact engagement portion 56 ofthe latch pawl member 44 abuts on the guide portion 53 of the mountingbracket 41 so that the latch pawl member 44 is forcibly rotated in thedirection of the arrow e by a pressing force from the guide portion 53.When the pedal arm 42 is rotated at maximum in the direction of thearrow b, the latch pawl 55 of the latch pawl member 44 abuts on theretreat portion 54 of the pawl teeth member 43 and is brought into theset state shown in FIG. 11. Thereby, the braking force is completelyreleased so that the vehicle is allowed to run.

{circle around (5)} Additional stepping from the braking released state(see FIG. 13 and FIG. 15)

When the braking force set by an initial braking operation is thought tobe insufficient, an additional stepping is conducted to additionallyincrease the braking force. Namely, in this case, the pedal arm 42 isstepped on from the braking released state shown in FIG. 13 and rotatedin the direction of the arrow a. Then, the support shaft 49 is movedforward along with the rotating operation and the latch pawl member 44is shifted from the “forward position” to the “reverse position”. Whenthe pedal arm 42 is further stepped on, the latch pawl member 44 ismoved relative to the position changing member 45 along with the forwardmovement thereof, and a portion of the latch pawl member 44 abutting onthe engaging portion 64 of the position changing member 45 is shiftedfrom the contact portion 57 to the side of the guide portion 58.

Along with the movement of the latch pawl member relative to theposition changing member 45, the latch pawl member 44 is urged to rotatein the direction of the arrow e by the urging force of the first urgingmember 46 and, finally, the latch pawl 55 is brought into lockingengagement with one of the pawl teeth 52 of the pawl teeth member 43.The position changing member 45 receives a pressing force from the latchpawl member 44 and is urged to rotate in the direction of the arrow f,whereby the first latch pawl 62 is brought into locking engagement withone of the pawl teeth 52 of the pawl teeth member 43 in addition to thesecond latch pawl 63, whereby the position changing member 45 isinhibited from further rotating in the direction of the arrow f.Finally, an action for inhibiting the position changing member 45 fromrotating is released along with the rotation of the latch pawl member 44in the direction of the arrow e, whereby the position changing member 45is rotated in the direction of the arrow e by the urging force of thesecond urging member 8 so that the second latch pawl 63 and the firstlatch pawl 62 are both removed from the pawl teeth member 43. Thereby,the transition to a state in which braking operation is conductible iscompleted.

After that, the pedal arm 42 is stepped on to a desired rotationalposition (namely, a position where a desired braking force can beobtained) and rotated in the direction of the arrow a. After therotation, when the stepping force applied to the pedal arm 42 isreleased, the latch pawl 55 of the latch pawl member 44 is brought intolocking engagement with one of the pawl teeth 52 of the pawl teethmember 43 and maintained in that state as shown in FIG. 12. Thereby, theadditional stepping operation is completed.

As the action in the braking release operation after the additionalstepping operation is the same as the that described in {circle around(3)} and {circle around (4)}, the description is omitted here.

As is described above, in the parking brake device according to thesecond embodiment, a required braking force can be generated andmaintained by stepping on pedal arm 42. Also, the maintained conditionis released and an operation for releasing the braking force byrestoring the pedal arm 42 is permitted by stepping on the pedal arm 42by a determined amount from the maintained condition. Moreover, thebraking force can be increased and maintained by stepping the pedal arm42 by an amount over the above determined amount from the maintainedcondition.

The parking brake for a vehicle according to the present invention has abraking force increasing function by which the braking force can beadditionally increased by a stepping operation in addition to functionswhich conventional foot-operated parking brakes have, namely, a functionof “setting a braking force by a stepping operation” and a function of“releasing a braking force by a stepping operation”. Thus, as comparedwith a conventional parking brake in which, when the braking force isnot sufficient, the braking action must be once released and thestepping operation must be conducted once again, the operation forincreasing braking force is easy and can be conducted more rapidly,thereby improving the operability. Moreover, since the braking force ismaintained through the additional stepping operation and the continuityof the braking force is secured, the reliability during operation isenhanced as compared with a conventional constitution in which thebraking force is discontinuous before and after the operation forincreasing the braking force and there exists a period during which thebraking force is vanished.

What is claimed is:
 1. A parking brake device for a vehicle having brakemeans, comprising: a pedal arm (2) having pawl teeth (12) andoperatively connected to said brake means such that said brake meansperforms a braking action when said pedal arm is stepped on; a latchpawl member (4) including a latch pawl (15) engageable with said pawlteeth (12) of said pedal arm (2), movable between a locked position inwhich said latch pawl (15) is in locking engagement with said pawl teeth(12) and an unlocked position in which said locking engagement of saidlatch pawl (15) with said pawl teeth (12) is released, said latch pawlmember (4) assuming said locked position, when said pedal arm (2) isstepped on, to maintain said pedal arm (2) in a stepped-on position atthe moment and assuming said unlocked position, when said pedal arm (2)is further stepped on from said stepped-on position by a determinedamount, to allow said pedal arm (2) to rotate in a direction opposite tothe stepping direction thereof; a position changing member (5) supportedon a common support shaft (9) for said latch pawl member (4) andprovided with a latch pawl (22) engageable with said pawl teeth (12) ofsaid pedal arm (2), said position changing member (5) being operativelyconnected to said pedal arm (2) and said latch pawl member (4) andadapted for shifting said latch pawl member (4) from said unlockedposition to said locked position by a stepping force applied to saidpedal arm (2) when said pedal arm (2) is stepped on by an amount oversaid determined amount; a first engaging portion (23) provided on saidposition changing member (5) and engageable with said latch pawl member(4) when said latch pawl member (4) assumes said locked position tomaintain said position changing member (5) at such a position that saidlatch pawl (22) is separated from said pawl teeth (12) of said pedal arm(2); and a second engaging portion (24) provided on said positionchanging member (5) and engageable with said latch pawl member (4) whensaid latch pawl member (4) assumes said unlocked position to maintainsaid position changing member (5) at such a position that said latchpawl (22) is engaged by said pawl teeth (12) of said pedal arm (2).
 2. Aparking brake device for a vehicle having brake means, comprising: apedal arm (42) rotatably mounted on a mounting bracket (41) fixedlydisposed on a vehicle body and operatively connected to said brake meanssuch that said brake means performs a braking action when said pedal armis stepped on; a pawl teeth member (43) including pawl teeth (52) andfixed to said mounting bracket (41); a latch pawl member (44) includinga latch pawl (55) engageable with said pawl teeth (52) of said pawlteeth member (43), movable between a locked position in which said latchpawl (55) is in locking engagement with said pawl teeth (52) and anunlocked position in which said locking engagement of said latch pawl(55) with said pawl teeth (52) is released, said latch pawl member (44)assuming said locked position, when said pedal arm (42) is stepped on,to maintain said pedal arm (42) in a stepped-on position at the momentand assuming said unlocked position, when said pedal arm (42) is furtherstepped on from said stepped-on position by a determined amount, toallow said pedal arm (42) to rotate in a direction opposite to thestepping direction thereof; a position changing member (45) supported ona common support shaft (49) for said latch pawl member (44) andoperatively connected to said pedal arm (42) and said latch pawl member(44) for shifting said latch pawl member (44) from said unlockedposition to said locked position by a stepping force applied to saidpedal arm (42) when said pedal arm (42) is stepped on by an amount oversaid determined amount; and an engaging portion (64) provided on saidposition changing member (45) and engageable with said latch pawl member(44) when said latch pawl member (44) assumes said locked position tomaintain the position of said position changing member (45), and withsaid latch pawl member (44) when said latch pawl member (44) assumessaid unlocked position to maintain the position of said latch pawlmember (44).